Two different cases of aggressive NK cell leukemia/lymphoma. (A) Peripheral blood shows increased large granular lymphocytes, most of which are mature-looking (case no. 36). The cell in the center is slightly less mature. (B) Buffy coat smear shows immature large granular lymphocytes with more open chromatin and distinct nucleoli (arrows) (case no. 37). Myeloid cells are seen in the background.